1 # SPDX-License-Identifier: GPL-2.0
3 # The 8250/16550 serial drivers. You shouldn't be in this list unless
4 # you somehow have an implicit or explicit dependency on SERIAL_8250.
8 tristate "8250/16550 and compatible serial support"
11 select SERIAL_MCTRL_GPIO if GPIOLIB
13 This selects whether you want to include the driver for the standard
14 serial ports. The standard answer is Y. People who might say N
15 here are those that are setting up dedicated Ethernet WWW/FTP
16 servers, or users that have one of the various bus mice instead of a
17 serial mouse and don't intend to use their machine's standard serial
20 To compile this driver as a module, choose M here: the
21 module will be called 8250.
22 [WARNING: Do not compile this driver as a module if you are using
23 non-standard serial ports, since the configuration information will
24 be lost when the driver is unloaded. This limitation may be lifted
27 BTW1: If you have a mouseman serial mouse which is not recognized by
28 the X window system, try running gpm first.
30 BTW2: If you intend to use a software modem (also called Winmodem)
31 under Linux, forget it. These modems are crippled and require
32 proprietary drivers which are only available under Windows.
34 Most people will say Y or M here, so that they can use serial mice,
35 modems and similar devices connecting to the standard serial ports.
37 config SERIAL_8250_DEPRECATED_OPTIONS
38 bool "Support 8250_core.* kernel options (DEPRECATED)"
39 depends on SERIAL_8250
42 In 3.7 we renamed 8250 to 8250_core by mistake, so now we have to
43 accept kernel parameters in both forms like 8250_core.nr_uarts=4 and
44 8250.nr_uarts=4. We now renamed the module back to 8250, but if
45 anybody noticed in 3.7 and changed their userspace we still have to
46 keep the 8250_core.* options around until they revert the changes
49 If 8250 is built as a module, this adds 8250_core alias instead.
51 If you did not notice yet and/or you have userspace from pre-3.7, it
52 is safe (and recommended) to say N here.
54 config SERIAL_8250_PNP
55 bool "8250/16550 PNP device support" if EXPERT
56 depends on SERIAL_8250 && PNP
59 This builds standard PNP serial support. You may be able to
60 disable this feature if you only need legacy serial support.
62 config SERIAL_8250_16550A_VARIANTS
63 bool "Support for variants of the 16550A serial port"
64 depends on SERIAL_8250
67 The 8250 driver can probe for many variants of the venerable 16550A
68 serial port. Doing so takes additional time at boot.
70 On modern systems, especially those using serial only for a simple
71 console, you can say N here.
73 config SERIAL_8250_FINTEK
74 bool "Support for Fintek variants"
75 depends on SERIAL_8250
77 Selecting this option will add support for the RS232 and RS485
78 capabilities of the Fintek F81216A LPC to 4 UART as well similar
81 If this option is not selected the device will be configured as a
82 standard 16550A serial port, however the device may not function
83 correctly without this option enabled.
87 config SERIAL_8250_CONSOLE
88 bool "Console on 8250/16550 and compatible serial port"
89 depends on SERIAL_8250=y
90 select SERIAL_CORE_CONSOLE
91 select SERIAL_EARLYCON
93 If you say Y here, it will be possible to use a serial port as the
94 system console (the system console is the device which receives all
95 kernel messages and warnings and which allows logins in single user
96 mode). This could be useful if some terminal or printer is connected
99 Even if you say Y here, the currently visible virtual console
100 (/dev/tty0) will still be used as the system console by default, but
101 you can alter that using a kernel command line option such as
102 "console=ttyS1". (Try "man bootparam" or see the documentation of
103 your boot loader (grub or lilo or loadlin) about how to pass options
104 to the kernel at boot time.)
106 If you don't have a VGA card installed and you say Y here, the
107 kernel will automatically use the first serial line, /dev/ttyS0, as
110 You can set that using a kernel command line option such as
111 "console=uart8250,io,0x3f8,9600n8"
112 "console=uart8250,mmio,0xff5e0000,115200n8".
113 and it will switch to normal serial console when the corresponding
115 "earlycon=uart8250,io,0x3f8,9600n8"
116 "earlycon=uart8250,mmio,0xff5e0000,115200n8".
117 it will not only setup early console.
121 config SERIAL_8250_PARISC
123 depends on SERIAL_8250 && PARISC
126 config SERIAL_8250_DMA
127 bool "DMA support for 16550 compatible UART controllers" if EXPERT
128 depends on SERIAL_8250 && DMADEVICES=y
131 This builds DMA support that can be used with 8250/16650
132 compatible UART controllers that support DMA signaling.
134 config SERIAL_8250_PCILIB
137 config SERIAL_8250_PCI
138 tristate "8250/16550 PCI device support"
139 depends on SERIAL_8250 && PCI
140 select SERIAL_8250_PCILIB
143 This builds standard PCI serial support. You may be able to
144 disable this feature if you only need legacy serial support.
146 Note that serial ports on NetMos 9835 Multi-I/O cards are handled
147 by the parport_serial driver, enabled with CONFIG_PARPORT_SERIAL.
149 config SERIAL_8250_EXAR
150 tristate "8250/16550 Exar/Commtech PCI/PCIe device support"
151 depends on SERIAL_8250 && PCI
154 This builds support for XR17C1xx, XR17V3xx and some Commtech
155 422x PCIe serial cards that are not covered by the more generic
156 SERIAL_8250_PCI option.
158 config SERIAL_8250_HP300
160 depends on SERIAL_8250 && HP300
163 config SERIAL_8250_CS
164 tristate "8250/16550 PCMCIA device support"
165 depends on PCMCIA && SERIAL_8250
167 Say Y here to enable support for 16-bit PCMCIA serial devices,
168 including serial port cards, modems, and the modem functions of
169 multi-function Ethernet/modem cards. (PCMCIA- or PC-cards are
170 credit-card size devices often used with laptops.)
172 To compile this driver as a module, choose M here: the
173 module will be called serial_cs.
177 config SERIAL_8250_MEN_MCB
178 tristate "MEN MCB UART device support"
179 depends on MCB && SERIAL_8250
181 This enables support for FPGA based UARTs found on many MEN
182 boards. This driver enables support for the 16z025, 16z057
185 To compile this driver as a module, chose M here: the
186 module will be called 8250_men_mcb.
189 config SERIAL_8250_NR_UARTS
190 int "Maximum number of 8250/16550 serial ports"
191 depends on SERIAL_8250
194 Set this to the number of serial ports you want the driver
195 to support. This includes any ports discovered via ACPI or
196 PCI enumeration and any ports that may be added at run-time
197 via hot-plug, or any ISA multi-port serial cards.
199 config SERIAL_8250_RUNTIME_UARTS
200 int "Number of 8250/16550 serial ports to register at runtime"
201 depends on SERIAL_8250
202 range 0 SERIAL_8250_NR_UARTS
205 Set this to the maximum number of serial ports you want
206 the kernel to register at boot time. This can be overridden
207 with the module parameter "nr_uarts", or boot-time parameter
210 config SERIAL_8250_EXTENDED
211 bool "Extended 8250/16550 serial driver options"
212 depends on SERIAL_8250
214 If you wish to use any non-standard features of the standard "dumb"
215 driver, say Y here. This includes HUB6 support, shared serial
216 interrupts, special multiport support, support for more than the
217 four COM 1/2/3/4 boards, etc.
219 Note that the answer to this question won't directly affect the
220 kernel: saying N will just cause the configurator to skip all
221 the questions about serial driver options. If unsure, say N.
223 config SERIAL_8250_MANY_PORTS
224 bool "Support more than 4 legacy serial ports"
225 depends on SERIAL_8250_EXTENDED
227 Say Y here if you have dumb serial boards other than the four
228 standard COM 1/2/3/4 ports. This may happen if you have an AST
229 FourPort, Accent Async, Boca (read the Boca mini-HOWTO, available
230 from <https://www.tldp.org/docs.html#howto>), or other custom
231 serial port hardware which acts similar to standard serial port
232 hardware. If you only use the standard COM 1/2/3/4 ports, you can
233 say N here to save some memory. You can also say Y if you have an
234 "intelligent" multiport card such as Digiboards, etc.
237 # Multi-port serial cards
240 config SERIAL_8250_FOURPORT
241 tristate "Support Fourport cards"
242 depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
244 Say Y here if you have an AST FourPort serial board.
246 To compile this driver as a module, choose M here: the module
247 will be called 8250_fourport.
249 config SERIAL_8250_ACCENT
250 tristate "Support Accent cards"
251 depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
253 Say Y here if you have an Accent Async serial board.
255 To compile this driver as a module, choose M here: the module
256 will be called 8250_accent.
258 config SERIAL_8250_ASPEED_VUART
259 tristate "Aspeed Virtual UART"
260 depends on SERIAL_8250
262 depends on MFD_SYSCON
263 depends on ARCH_ASPEED || COMPILE_TEST
266 If you want to use the virtual UART (VUART) device on Aspeed
267 BMC platforms, enable this option. This enables the 16550A-
268 compatible device on the local LPC bus, giving a UART device
269 with no physical RS232 connections.
271 config SERIAL_8250_BOCA
272 tristate "Support Boca cards"
273 depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
275 Say Y here if you have a Boca serial board. Please read the Boca
276 mini-HOWTO, available from <https://www.tldp.org/docs.html#howto>
278 To compile this driver as a module, choose M here: the module
279 will be called 8250_boca.
281 config SERIAL_8250_EXAR_ST16C554
282 tristate "Support Exar ST16C554/554D Quad UART"
283 depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
285 The Uplogix Envoy TU301 uses this Exar Quad UART. If you are
286 tinkering with your Envoy TU301, or have a machine with this UART,
289 To compile this driver as a module, choose M here: the module
290 will be called 8250_exar_st16c554.
292 config SERIAL_8250_HUB6
293 tristate "Support Hub6 cards"
294 depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
296 Say Y here if you have a HUB6 serial board.
298 To compile this driver as a module, choose M here: the module
299 will be called 8250_hub6.
301 config SERIAL_8250_PCI1XXXX
302 tristate "Microchip 8250 based serial port"
303 depends on SERIAL_8250 && PCI
304 select SERIAL_8250_PCILIB
306 Select this option if you have a setup with Microchip PCIe
307 Switch with serial port enabled and wish to enable 8250
308 serial driver for the serial interface. This driver support
309 will ensure to support baud rates upto 1.5Mpbs.
312 # Misc. options/drivers.
315 config SERIAL_8250_SHARE_IRQ
316 bool "Support for sharing serial interrupts"
317 depends on SERIAL_8250_EXTENDED
319 Some serial boards have hardware support which allows multiple dumb
320 serial ports on the same board to share a single IRQ. To enable
321 support for this in the serial driver, say Y here.
323 config SERIAL_8250_DETECT_IRQ
324 bool "Autodetect IRQ on standard ports (unsafe)"
325 depends on SERIAL_8250_EXTENDED
327 Say Y here if you want the kernel to try to guess which IRQ
328 to use for your serial port.
330 This is considered unsafe; it is far better to configure the IRQ in
331 a boot script using the setserial command.
335 config SERIAL_8250_RSA
336 bool "Support RSA serial ports"
337 depends on SERIAL_8250_EXTENDED
339 Say Y here if you have a IODATA RSA-DV II/S ISA card and
340 would like to use its >115kbps speeds.
341 You will need to provide module parameter "probe_rsa", or boot-time
342 parameter 8250.probe_rsa with I/O addresses of this card then.
344 If you don't have such card, or if unsure, say N.
346 config SERIAL_8250_DWLIB
349 config SERIAL_8250_ACORN
350 tristate "Acorn expansion card serial port support"
351 depends on ARCH_ACORN && SERIAL_8250
353 If you have an Atomwide Serial card or Serial Port card for an Acorn
354 system, say Y to this option. The driver can handle 1, 2, or 3 port
355 cards. If unsure, say N.
357 config SERIAL_8250_BCM2835AUX
358 tristate "BCM2835 auxiliar mini UART support"
359 depends on ARCH_BCM2835 || COMPILE_TEST
360 depends on SERIAL_8250 && SERIAL_8250_SHARE_IRQ
362 Support for the BCM2835 auxiliar mini UART.
364 Features and limitations of the UART are
365 Registers are similar to 16650 registers,
366 set bits in the control registers that are unsupported
367 are ignored and read back as 0
368 7/8 bit operation with 1 start and 1 stop bit
369 8 symbols deep fifo for rx and tx
370 SW controlled RTS and SW readable CTS
371 Clock rate derived from system clock
372 Uses 8 times oversampling (compared to 16 times for 16650)
373 Missing break detection (but break generation)
374 Missing framing error detection
376 Missing receive time-out interrupt
377 Missing DCD, DSR, DTR and RI signals
381 config SERIAL_8250_FSL
382 tristate "Freescale 16550 UART support" if COMPILE_TEST && !(PPC || ARM || ARM64)
383 depends on SERIAL_8250
384 default SERIAL_8250 if PPC || ARM || ARM64
386 Selecting this option enables a workaround for a break-detection
387 erratum for Freescale 16550 UARTs in the 8250 driver. It also
388 enables support for ACPI enumeration.
390 config SERIAL_8250_DFL
391 tristate "DFL bus driver for Altera 16550 UART"
392 depends on SERIAL_8250 && FPGA_DFL
394 This option enables support for a Device Feature List (DFL) bus
395 driver for the Altera 16550 UART. One or more Altera 16550 UARTs
396 can be instantiated in a FPGA and then be discovered during
397 enumeration of the DFL bus.
399 To compile this driver as a module, chose M here: the
400 module will be called 8250_dfl.
402 config SERIAL_8250_DW
403 tristate "Support for Synopsys DesignWare 8250 quirks"
404 depends on SERIAL_8250
405 select SERIAL_8250_DWLIB
407 Selecting this option will enable handling of the extra features
408 present in the Synopsys DesignWare APB UART.
410 config SERIAL_8250_EM
411 tristate "Support for Emma Mobile integrated serial port"
412 depends on SERIAL_8250 && HAVE_CLK
413 depends on ARCH_RENESAS || COMPILE_TEST
415 Selecting this option will add support for the integrated serial
416 port hardware found on the Emma Mobile line of processors.
419 config SERIAL_8250_IOC3
420 tristate "SGI IOC3 8250 UART support"
421 depends on SERIAL_8250
422 depends on SGI_MFD_IOC3 || COMPILE_TEST
423 select SERIAL_8250_EXTENDED
424 select SERIAL_8250_SHARE_IRQ
426 Enable this if you have a SGI Origin or Octane machine. This module
427 provides basic serial support by directly driving the UART chip
428 behind the IOC3 device on those systems. Maximum baud speed is
429 38400bps using this driver.
431 config SERIAL_8250_RT288X
432 bool "Ralink RT288x/RT305x/RT3662/RT3883 serial port support"
433 depends on SERIAL_8250
434 default y if MIPS_ALCHEMY || SOC_RT288X || SOC_RT305X || SOC_RT3883 || SOC_MT7620
436 Selecting this option will add support for the alternate register
437 layout used by Ralink RT288x/RT305x, Alchemy Au1xxx, and some others.
440 config SERIAL_8250_OMAP
441 tristate "Support for OMAP internal UART (8250 based driver)"
442 depends on SERIAL_8250
443 depends on ARCH_OMAP2PLUS || ARCH_K3 || COMPILE_TEST
445 If you have a machine based on an Texas Instruments OMAP CPU you
446 can enable its onboard serial ports by enabling this option.
448 This driver uses ttyS instead of ttyO.
450 config SERIAL_8250_OMAP_TTYO_FIXUP
451 bool "Replace ttyO with ttyS"
452 depends on SERIAL_8250_OMAP=y && SERIAL_8250_CONSOLE
455 This option replaces the "console=ttyO" argument with the matching
456 ttyS argument if the user did not specified it on the command line.
457 This ensures that the user can see the kernel output during boot
458 which he wouldn't see otherwise. The getty has still to be configured
459 for ttyS instead of ttyO regardless of this option.
460 This option is intended for people who "automatically" enable this
461 driver without knowing that this driver requires a different console=
462 argument. If you read this, please keep this option disabled and
463 instead update your kernel command line. If you prepare a kernel for a
464 distribution or other kind of larger user base then you probably want
465 to keep this option enabled. Otherwise people might complain about a
466 not booting kernel because the serial console remains silent in case
467 they forgot to update the command line.
469 config SERIAL_8250_LPC18XX
470 tristate "NXP LPC18xx/43xx serial port support"
471 depends on SERIAL_8250 && OF && (ARCH_LPC18XX || COMPILE_TEST)
474 If you have a LPC18xx/43xx based board and want to use the
475 serial port, say Y to this option. If unsure, say Y.
477 config SERIAL_8250_MT6577
478 tristate "Mediatek serial port support"
479 depends on SERIAL_8250
480 depends on ARCH_MEDIATEK || COMPILE_TEST
482 If you have a Mediatek based board and want to use the
483 serial port, say Y to this option. If unsure, say N.
485 config SERIAL_8250_UNIPHIER
486 tristate "Support for UniPhier on-chip UART"
487 depends on SERIAL_8250
488 depends on ARCH_UNIPHIER || COMPILE_TEST
490 If you have a UniPhier based board and want to use the on-chip
491 serial ports, say Y to this option. If unsure, say N.
493 config SERIAL_8250_INGENIC
494 tristate "Support for Ingenic SoC serial ports"
495 depends on SERIAL_8250
496 depends on OF_FLATTREE
497 depends on MIPS || COMPILE_TEST
499 If you have a system using an Ingenic SoC and wish to make use of
500 its UARTs, say Y to this option. If unsure, say N.
502 config SERIAL_8250_LPSS
503 tristate "Support for serial ports on Intel LPSS platforms"
505 depends on SERIAL_8250 && PCI
506 depends on X86 || COMPILE_TEST
507 select SERIAL_8250_DWLIB
508 select DW_DMAC_CORE if SERIAL_8250_DMA
509 select DW_DMAC_PCI if (SERIAL_8250_DMA && X86_INTEL_LPSS)
512 Selecting this option will enable handling of the UART found on
513 various Intel platforms such as:
516 - Intel Quark X1000 SoC
517 that are not covered by the more generic SERIAL_8250_PCI option.
519 config SERIAL_8250_MID
520 tristate "Support for serial ports on Intel MID platforms"
522 depends on SERIAL_8250 && PCI
523 depends on X86 || COMPILE_TEST
524 select HSU_DMA if SERIAL_8250_DMA
525 select HSU_DMA_PCI if (HSU_DMA && X86_INTEL_MID)
528 Selecting this option will enable handling of the UART found on
529 Intel Medfield SOC and various other Intel platforms that is not
530 covered by the more generic SERIAL_8250_PCI option.
532 config SERIAL_8250_PERICOM
533 tristate "Support for Pericom and Acces I/O serial ports"
535 depends on SERIAL_8250 && PCI
537 Selecting this option will enable handling of the Pericom and Acces
538 I/O UARTs that are not covered by the more generic SERIAL_8250_PCI
541 config SERIAL_8250_PXA
542 tristate "PXA serial port support"
543 depends on SERIAL_8250
544 depends on ARCH_PXA || ARCH_MMP || COMPILE_TEST
546 If you have a machine based on an Intel XScale PXA2xx CPU you can
547 enable its onboard serial ports by enabling this option. The option is
548 applicable to both devicetree and legacy boards, and early console is
551 config SERIAL_8250_TEGRA
552 tristate "8250 support for Tegra serial ports"
554 depends on SERIAL_8250
555 depends on ARCH_TEGRA || COMPILE_TEST
557 Select this option if you have machine with an NVIDIA Tegra SoC and
558 wish to enable 8250 serial driver for the Tegra serial interfaces.
560 config SERIAL_8250_BCM7271
561 tristate "Broadcom 8250 based serial port"
562 depends on SERIAL_8250 && (ARCH_BRCMSTB || COMPILE_TEST)
565 If you have a Broadcom STB based board and want to use the
566 enhanced features of the Broadcom 8250 based serial port,
567 including DMA support and high accuracy BAUD rates, say
568 Y to this option. If unsure, say N.
570 config SERIAL_OF_PLATFORM
571 tristate "Devicetree based probing for 8250 ports"
572 depends on SERIAL_8250 && OF
574 This option is used for all 8250 compatible serial ports that
575 are probed through devicetree, including Open Firmware based
576 PowerPC systems and embedded systems on architectures using the
577 flattened device tree format.